Rojanasakul Y, Shi X, Deshpande D, Liang W W, Wang L Y
Department of Basic Pharamaceutical Sciences, West Virginia University, Morgantown 26506, USA.
Biochim Biophys Acta. 1996 Jan 17;1315(1):21-8. doi: 10.1016/0925-4439(95)00090-9.
The successful prevention of hydrogen peroxide-induced alveolar permeability alterations and cell injury by transferrin-catalase conjugate is described in this study. Permeability alterations and cell injury were induced in cultured alveolar epithelial monolayers by hydrogen peroxide. Transepithelial transport of a permeability marker, [14C] mannitol, and cellular nuclear fluorescence of a membrane integrity indicator, propidium iodide, were used to quantitate epithelial permeability and damage respectively. Hydrogen peroxide (0.1 - 10 mM) induced a dose-dependent increase in both alveolar permeability and cellular damage; however, the oxidant effect on monolayer permeability did not require prior cell damage. Electron spin resonance measurements using the spin trap 5,5-dimethyl-l-pyrroline-N-oxide indicated the formation of hydroxyl radicals in hydrogen peroxide-treated cells. Chelation of the cellular pool of iron by deferoxamine inhibited radical formation and helped protect the cells from oxidative changes. Prior treatment of the cells with catalase (0.1 U-10 U/ml) had minimal protective effects on cell injury and permeability alterations. In contrast, transferrin-catalase conjugate, at the same concentration range, exhibited much improved protective effects on the cells in response to oxidant stress. This enhanced protection was found to correlate well with an increase in cellular uptake of the enzyme conjugate via the transferrin receptor endocytosis pathway. Effective protection by the enzyme conjugate was shown to require both the antioxidant enzyme moiety and the cognate moiety for the cell surface receptor. These findings indicate the potential therapeutic merit of transferrin-catalase conjugate for the treatment of pathological processes in the lung, whenever oxidative stress is involved.
本研究描述了转铁蛋白 - 过氧化氢酶偶联物成功预防过氧化氢诱导的肺泡通透性改变和细胞损伤的情况。过氧化氢在培养的肺泡上皮单层细胞中诱导通透性改变和细胞损伤。通透性标志物[¹⁴C]甘露醇的跨上皮转运以及膜完整性指示剂碘化丙啶的细胞核荧光分别用于定量上皮通透性和损伤情况。过氧化氢（0.1 - 10 mM）诱导肺泡通透性和细胞损伤呈剂量依赖性增加；然而，氧化剂对单层通透性的影响并不需要预先的细胞损伤。使用自旋捕捉剂5,5 - 二甲基 - 1 - 吡咯啉 - N - 氧化物的电子自旋共振测量表明，过氧化氢处理的细胞中形成了羟基自由基。去铁胺对细胞内铁池的螯合作用抑制了自由基的形成，并有助于保护细胞免受氧化变化的影响。用过氧化氢酶（0.1 U - 10 U/ml）预先处理细胞对细胞损伤和通透性改变的保护作用极小。相比之下，在相同浓度范围内，转铁蛋白 - 过氧化氢酶偶联物对氧化应激反应的细胞表现出显著改善的保护作用。发现这种增强的保护作用与通过转铁蛋白受体胞吞途径增加的酶偶联物细胞摄取密切相关。结果表明，酶偶联物的有效保护作用需要抗氧化酶部分和细胞表面受体的同源部分。这些发现表明，转铁蛋白 - 过氧化氢酶偶联物在涉及氧化应激的肺部病理过程治疗中具有潜在的治疗价值。
